Heredity and Evolution


In evolutionary terms, can we say which among bacteria, spiders, fish and chimpanzees have a ‘better body design’ why or why not ?


No, because different designs are the product of evolution and different species have different body design to suit or adapt to their environment.


Heredity and Evolution

Q 1.

Choose the one term from the following which includes the other three :
broccoli, wild cabbage, cauliflower, cabbage

Q 2.

What constitutes the link between one generation and the next ?

Q 3.

Which of the two, sperm or ovum, decides the sex of the child ?

Q 4.

Which of the processes, sexual reproduction or asexual reproduction, brings about maximum variations in the offsprings ?

Q 5.

Gregor Mendel’s first law of genetics states “Of a pair of contrasted characters, only one can be represented in a gamete by its internal ‘factor’.
(a) Give the modern name for this ‘factor’.
(b) State where these factors are found in gametes.

Q 6.

Where did life originate on the earth ?

Q 7.

Why are the small numbers of surviving tigers a cause of worry from the point of view of genetics ?

Q 8.

Can the wing of butterfly and the wing of a bat be considered homologous organs ? Why or why not ?

Q 9.

Explain the importance of fossils in deciding evolutionary relationships.

Q 10.

Define homologous organs.

Q 11.

Define evolution. Describe the contribution of Lamarck.

Q 12.

What type of plants were used by Mendel for conducting his experiments on inheritance ?

Q 13.

Name two animals having homologous organs and two having analogous organs. Name these organs.

Q 14.

Name the various tools of tracing evolutionary relationships which have been used for studying human evolution.

Q 15.

a) Name the scientist who gave the theory of origin of life on earth. What is this theory ?
(b) How are those species which are now ‘extinct’ studied ?

Q 16.

A study found that children with light-coloured eyes are likely to have parents with light-coloured eyes. On this basis, can we say anything about whether the light eye colour trait is dominant or recessive? Why or why not?

Q 17.

Outline a project which alms to find the dominant coat colour in dogs.

Q 18.

During which stage can the chromosomes be seen clearly? Write the features of the eukaryotic and prokaryotic chromosomes.

Q 19.

Who provided the evidence of DNA as the genetic material? Write the names of the components of the DNA molecule.

Q 20.

How do embryological studies provide evidence for evolution?

Q 21.

Name one variation in humans connected with ears.

Q 22.

Which of the following combinations of sex chromosomes produce a male child : XX or XY ?

Q 23.

What are the four blood groups in humans ?

Q 24.

Name one reptile in each case where higher incubation temperature leads to the development of : (a) male progeny, (b) female progeny.

Q 25.

Fill in the following blanks with suitable words :Fill in the following blanks with suitable words :
(a) Genes always work in …………………
(b) In pea plants, the gene for dwarfness is………………… whereas that for tallness is…………………
(c) Most people have………………… earlobes but some have………………… earlobes.
(d) A human gamete contains………………… chromosomes whereas a normal body cell has………………… chromosomes in it.
(e) All races of man have………………… blood groups.
(f) The………………… chromosomes for a………………… are XX whereas that for a………………… are XY.

Q 26.

(a) If a normal human cell has 46 chromosomes, how many chromosomes will be there in a human (;) sperm cell, and (ii) zygote ?
(b) What sizes of plants are produced if both parents have genes Tt ?

Q 27.

In a human, how many chromosmes are present in :
(a) a brain cell ?
(b) a sperm in the testes ?
(c) an egg which has just been produced by the ovary ?
(d) a skin cell ?
(e) a fertilised egg ?

Q 28.

(a) Why did Mendel choose pea plants for conducting his experiments on inheritance ?
(b) State Mendel’s second law of inheritance.

Q 29.

(a) What do you understand by the term ‘variation’ ?
(b) Name two human traits which show variation.

Q 30.

Name the scientist who gave the theory of evolution.

Q 31.

Why are human beings who look so different from each other in terms of size, colour and looks said to belong to the same species ?

Q 32.

Does geographical isolation of individuals of a species lead to the formation of a new species ? Provide a suitable explanation for your answer.

Q 33.

Bacteria have a simpler body plan when compared with human beings. Does it mean that human beings are more evolved than bacteria? Provide a suitable explanation.

Q 34.

A man with blood group A marries a woman with blood O and their daughter has blood group O. Is this information enough to tell you which of the traits  blood group A or O is dominant ? Why or why not ?

Q 35.

Why are the small numbers of surviving tigers a cause of worry from the point of view of genetics ?

Q 36.

What evidence do we have for the origin of life from inanimate matter?

Q 37.

Define variation.

Q 38.

Write the expanded form of DNA.

Q 39.

What is a sex chromosome?

Q 40.

What evidence do we have for the origin of life from inanimate matter? [All India]

Q 41.

Explain with examples how the following are evidences in favour of evolution in organisms.  (i) Homologous organs (ii) Analogous organs (iii) Fossils [Delhi]

Q 42.

How are fossils formed? Describe, in brief, two methods of determining the age of fossils. [All India]

Q 43.

Explain with an example, how genes control the characteristics (or traits).

Q 44.

Name the ancestor of the following :
Broccoli, Kohlrabi, Kale

Q 45.

Name the famous book written by Charles Robert Darwin.

Q 46.

Name five varieties of vegetables which have been produced from ‘wild cabbage’ by the process of artificial selection.

Q 47.

What is meant by acquired and inherited traits ? Explain with one example each.

Q 48.

Why are the traits acquired during the lifetime of an individual not inherited ?

Q 49.

What are fossils ? Giving one example, explain how fossils provide evidence for evolution.

Q 50.

(a) What is meant by a species ? Give two examples of plant species and two of animals.
(b) State the various factors which could lead to the formation of new species.